Seat frame

ABSTRACT

To reduce the weight of a cross member bridged between right and left sides of a seat frame. A seat frame includes an upper frame forming an upper portion of a seat back frame, and a cross member bridged at the upper frame. The cross member includes right and left end portions in a seat width direction, the right and left end portions being fixed to the upper frame; and a first recessed portion that is recessed upward or downward and provided between the right and left end portions. The first recessed portion is provided at a center portion of the cross member in the seat width direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Entry application of PCTApplication No. PCT/JP2017/028846, filed Aug. 8, 2017, which claims thepriority benefit of Japanese Patent Application No. JP 2016-156889,filed on Aug. 9, 2016 and PCT Application No. PCT/JP2017/013793, filedMar. 31, 2017, the contents of each being incorporated herein byreference.

BACKGROUND

The present disclosure relates to a seat frame of a vehicle seat, andparticularly relates to a seat frame configured so that the weightthereof can be reduced.

Weight reduction has been demanded for a seat frame forming a frameworkof a seat mounted on a conveyance such as an automobile. For example, inJapanese Patent Publication JP 2015-067168, a thin plate-shaped frame isused for a side frame forming a side portion of a seat frame, and inthis manner, the weight of the frame is reduced.

Some frames are configured such that a cross member bridged betweenright and left sides is provided at an upper portion of a seat backframe. Weight reduction in such a cross member is also an issue.

SUMMARY

The present disclosure has been made in view of the above-describedproblem, and an embodiment of the present disclosure provides a seatframe configured so that the weight of a cross member bridged betweenright and left sides of the seat frame can be reduced.

According to an embodiment, the above-described problem is solved by aseat frame of a vehicle seat, which includes an upper frame forming anupper portion of a seat back frame and a cross member bridged at theupper frame. The cross member includes right and left end portions in aseat width direction, the right and left end portions being fixed to theupper frame; and a first recessed portion that is recessed upward ordownward and provided between the right and left end portions. Accordingto the above-described seat frame, the weight of the cross member can bereduced as compared to the case of providing no recessed portion at thecross member. Thus, the weight of the cross member bridged between rightand left sides of the seat frame can be reduced.

In the above-described seat frame, the first recessed portion ispreferably provided at a center portion of the cross member in the seatwidth direction. The first recessed portion is provided at a positionfacing an occupant as described above, and therefore, a feeling ofsitting on the seat can be improved. Moreover, according to theabove-described seat frame, a space where a member is arranged can beprovided in the vicinity of the center portion of the cross member.

In the above-described seat frame, the cross member preferably includesa reinforcement portion formed at the first recessed portion. With thisconfiguration, lowering of the stiffness of the vicinity of the firstrecessed portion of the cross member can be suppressed.

In the above-described seat frame, the cross member preferably includeswide portions provided on right and left sides of the first recessedportion in the seat width direction, and the reinforcement portion ispreferably formed across the first recessed portion and both of the wideportions. With this configuration, the stiffness of the cross member canbe improved.

In the above-described seat frame, the cross member is preferablyprovided with a through-hole. With this configuration, the weight of thecross member can be further reduced.

In the above-described seat frame, the through-hole is preferably formedat each wide portion. The through-hole is formed at the wide portion asdescribed above, and therefore, a larger through-hole can be formed ascompared to the case of forming the through-hole at the first recessedportion. Thus, the weight of the cross member can be further reduced.

In the above-described seat frame, the through-hole is preferably formedat the reinforcement portion at each wide portion. With thisconfiguration, weight reduction in the cross member can be realized, andlowering of the stiffness of the cross member can be also suppressed.

In the above-described seat frame, at least part of each wide portion ispreferably curved to protrude backward. With this configuration, thestiffness of the cross member can be improved. Moreover, the crossmember can be formed in a shape matching the body shape of the occupant,and therefore, the feeling of sitting on the seat can be improved.

In the above-described seat frame, the seat frame preferably furtherincludes a second recessed portion different from the first recessedportion, the second recessed portion being provided at least at one ofan upper or lower end of the cross member. With this configuration, theweight of the cross member can be further reduced. Moreover, a membersuch as a cover stop member can be stopped at the second recessedportion. Thus, the number of components forming the seat can be reduced.Consequently, the weight of the seat can be reduced.

In the above-described seat frame, the seat frame preferably furtherincludes a flange portion provided at least at one of the upper or lowerend of the cross member. The flange portion is preferably formed at aposition facing the first recessed portion in an upper-to-lowerdirection. With this configuration, lowering of the stiffness of thefirst recessed portion can be suppressed.

According to an embodiment, the weight of the cross member bridgedbetween the right and left sides of the seat frame can be reduced.According to an embodiment, the feeling of sitting on the seat can beimproved. According to an embodiment, lowering of the stiffness of thevicinity of the first recessed portion of the cross member can besuppressed. According to an embodiment, the stiffness of the crossmember can be improved. According to an embodiment, a largerthrough-hole can be formed at the cross member. According to anembodiment, weight reduction in the cross member can be realized, andlowering of the stiffness of the cross member can be suppressed.According to an embodiment, the number of components forming the seatcan be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a seat frame according to the presentembodiment.

FIG. 2 is a left side view of a seat back frame.

FIG. 3A is an outer side view of a side frame.

FIG. 3B is a rear view of the side frame of FIG. 3A. FIG. 3C is an innerside view of the side frame.

FIG. 4 is an enlarged partial view of the periphery of a second couplingbracket from a view point IV of FIG. 1.

FIG. 5A is an outer side view of a first coupling bracket.

FIG. 5B is a rear view of the first coupling bracket of FIG. 5A.

FIG. 5C is an inner side view of the first coupling bracket of FIG. 5A.

FIG. 6A is an outer side view of the second coupling bracket of FIG. 4.

FIG. 6B is a rear view of the second coupling bracket of FIG. 4.

FIG. 6C is an inner side view of the second coupling bracket.

FIG. 7 is an enlarged partial view of a front side of the seat frame.

FIG. 8 is an enlarged partial view of a rear side of the seat frame.

FIG. 9 is a sectional view along an IX-IX line of FIG. 7.

FIG. 10 is a sectional view along an X-X line of FIG. 7.

FIG. 11 is an enlarged partial view from a view point XI of FIG. 7.

FIG. 12A is a view of a variation of reinforcement portions provided atthe side frame.

FIG. 12B is a view of another variation of the reinforcement portionsprovided at the side frame.

FIG. 12C is a view of still another variation of the reinforcementportions provided at the side frame.

FIG. 12D is a view of still another variation of the reinforcementportions provided at the side frame.

FIG. 13 is a view of an upper portion of a seat frame according to asecond embodiment.

FIG. 14 is a sectional view along an XIV-XIV line of FIG. 13.

FIG. 15 is a sectional view along an XV-XV line of FIG. 13.

FIG. 16 is a sectional view along an XVI-XVI line of FIG. 13.

FIG. 17 is a sectional view along an XVII-XVII line of FIG. 13.

FIG. 18 is a view for describing a state in which a blower and stopmembers are attached to a seat back frame according to the secondembodiment.

DETAILED DESCRIPTION

Hereinafter, a seat frame 1 according to an embodiment (hereinafterreferred to as a “present embodiment”) of the present disclosure isdescribed with reference to FIGS. 1 to 18. The seat frame 1 forms aframework of a vehicle seat mounted on a vehicle. Note that theembodiments described below are set forth merely as examples for thesake of easy understanding of the present disclosure, and are notintended to limit the embodiments. That is, changes and modificationscan be made to the shapes, dimensions, arrangements, etc. of membersdescribed below without departing from the gist of the presentdisclosure, and needless to say, the invention includes equivalentsthereof.

In the description below, a “front-to-rear direction” means afront-to-rear direction as viewed from a seated person on the vehicleseat, and is a direction coincident with a traveling direction of thevehicle. A “seat width direction” means a horizontal width direction ofthe vehicle seat, and is coincident with a right-to-left direction asviewed from the seated person on the vehicle seat. Moreover, an“upper-to-lower direction” means a height direction of the vehicle seat,and is coincident with an upper-to-lower direction when the vehicle seatis viewed from the front.

Outline of Seat Frame 1

First, an outline of a configuration of the seat frame 1 is describedwith reference to FIG. 1. As illustrated in FIG. 1, the seat frame 1mainly includes a seat back frame 10 and a seat cushion frame 20. Theseat back frame 10 forms a framework of a backrest portion of the seatframe 1, and the seat cushion frame 20 forms a framework of a seatingportion of the seat frame 1.

As illustrated in FIG. 1, the seat back frame 10 includes an invertedU-shaped upper frame 11, a pair of side frames 12 forming right and leftend portions in the seat width direction, and a lower frame 13 couplinglower end portions of the pair of side frames 12.

The upper frame 11 is welded to the side frames 12 at upper frame sideportions 11A forming both lower portions of the upper frame 11.Moreover, headrest attachment portions 17 are, by welding, attached toan upper end of the upper frame 11. The headrest attachment portions 17are tubular bodies into which two headrest stays hanging down from anot-shown headrest are inserted.

A cross member 14 is bridged between both end portions of the upperframe 11 above the upper frame side portions 11A. Right and left endportions 14B of the cross member 14 are welded and fixed to right andleft bent portions of the upper frame 11. Note that the bent portion ofthe upper frame 11 is a portion of the upper frame 11 coupling a portionattached to the headrest attachment portion 17 and a portion attached tothe side frame 12. In the case of demanding weight reduction, a recessedportion 14A recessed upward of the seat is formed between the right andleft end portions 14B of the cross member 14. Specifically, the recessedportion 14A is formed at a center portion of the cross member 14 in theseat width direction. In other words, the recessed portion 14A isprovided between the right and left headrest attachment portions 17. Asdescribed above, the recessed portion 14A is formed at the cross member14 of the seat frame 1, and in this manner, the weight of the seat frame1 is reduced. Note that the recessed portion 14A is formed at a lowerend of the cross member 14, but may be formed at an upper end. In thecase of forming the recessed portion 14A at the upper end, the recessedportion 14A is a portion recessed downward of the seat. Alternatively,the recessed portion 14A may be formed at each of the upper and lowerends of the cross member 14.

As illustrated in FIG. 1, a rotary shaft 16 for reclining units 40 isattached between the lower end portions of the right and left sideframes 12 with the rotary shaft 16 penetrating the right and left sideframes 12. Note that a reclining operation section is operated tooperate the reclining units 40, and in this manner, the angle of theseat back frame 10 with respect to the seat cushion frame 20 can beadjusted.

A pressure receiving member 15 configured to receive a load from anoccupant is bridged at a center portion of the seat back frame 10. Thepressure receiving member 15 described herein includes a support portion15A, a wire 15B, and wires 15C. The support portion 15A is configured tosupport the back of the occupant, and includes an elastic member such asa plate spring or an S-spring, for example. Note that a surface of thesupport portion 15A at the front of the seat is referred to as a“support surface.” The wire 15B is stopped at the support portion 15Aand a front wall portion 13B of the lower frame 13. Specifically, thewire 15B is stopped at the front wall portion 13B of the lower frame 13by means of clips 50 fitted in through-holes formed at the front wallportion 13B. The wires 15C are stopped at side portions of the supportportion 15A and the side frames 12. As described above, the supportportion 15A is fixed to the seat back frame 10 with the wire 15B and thewires 15C.

Next, the seat cushion frame 20 is described. As illustrated in FIG. 1,the seat cushion frame 20 is in an outer square frame shape as viewedfrom above. Moreover, the seat cushion frame 20 includes, as maincomponents, cushion side frames 22A, 22B each formed at right and leftend portions in the seat width direction, a pan frame 21 forming a frontend portion of the seat cushion frame 20, and a coupling pipe 23coupling the right and left cushion side frames 22A, 22B. For example,the coupling pipe 23 is a hollow member such as a round pipe, and a rearend of a pressure receiving member 24 configured to support the buttocksof the occupant is attached to the coupling pipe 23.

As illustrated in FIG. 1, a first coupling bracket 18 is attached to anupper portion of a rear end portion of the left cushion side frame 22A.Moreover, the left side frame 12 is coupled to the first couplingbracket 18 via the reclining unit 40. Moreover, as illustrated in FIG.4, a second coupling bracket 19 is attached to an upper portion of arear end portion of the right cushion side frame 22B. Moreover, theright side frame 12 is coupled to the second coupling bracket 19 via thereclining unit 40. Note that details of configurations of the firstcoupling bracket 18 and the second coupling bracket 19 are describedbelow.

Configuration of Side Frame 12

Next, a configuration of the side frame 12 is described with referenceto FIGS. 2, 3A, 3B, and 3C. FIG. 2 is a left side view of the seat backframe 10. FIG. 3A is an outer side view of the side frame 12, FIG. 3B isa rear view of the side frame 12, and FIG. 3C is an inner side view ofthe side frame 12.

As illustrated in FIGS. 2, 3A, and 3C, a side frame side portion 12Aforming a side portion of the side frame 12 is provided with multiplethrough-holes including an airbag attachment hole 31A, an airbagattachment hole 31B, an airbag attachment hole 31C, and a through-hole31D. The airbag attachment hole 31A, the airbag attachment hole 31B, andthe airbag attachment hole 31C are through-holes used for attachment ofan airbag unit. The airbag unit described herein includes an airbagbody, webbing configured to guide an airbag in a deploying directionthereof, and an airbag attachment plate, for example. For example, theairbag attachment hole 31B and the airbag attachment hole 31C are holesfor attachment of the webbing of the airbag, and the airbag attachmenthole 31A is a hole into which a bolt extending from a retainer of theairbag body is inserted. The through-hole 31D is formed at a positionfacing a lower end of the upper frame side portion 11A, and the sideframe 12 and the upper frame 11 are welded to each other at thethrough-hole 31D.

As illustrated in FIGS. 2, 3A, and 3C, a first reinforcement portion 30Aextending along a rear edge 12C of the side frame side portion 12Aforming the side portion of the side frame 12 is formed at the sideframe side portion 12A. Note that the rear edge 12C is a bent portion asa boundary between the side frame side portion 12A forming a sidesurface of the side frame 12 and a side frame rear portion 12B forming arear surface of the side frame 12. The first reinforcement portion 30Ais, for example, configured as a bead portion formed in such a mannerthat part of the side frame side portion 12A is recessed inward of theseat by pressing. The first reinforcement portion 30A described hereinis provided at least at a wide portion 12D having the greatest width atthe side frame side portion 12A. In the present embodiment, the firstreinforcement portion 30A is provided along the rear edge 12C from aposition facing the through-hole 31D to a position facing the airbagattachment hole 31C in the upper-to-lower direction. That is, the firstreinforcement portion 30A is provided at least at a position at whichthe side frame 12 and the upper frame side portion 11A overlap with eachother, and therefore, the strength of a joint portion between the sideframe 12 and the upper frame 11 can be enhanced. Note that an upper endof the first reinforcement portion 30A may be positioned above theposition of welding between the side frame 12 and the upper frame 11.Moreover, as illustrated in FIG. 2, the first reinforcement portion 30Ais provided at such a position that the first reinforcement portion 30Aoverlaps with the upper frame 11 and the cushion side frames 22A, 22B inthe upper-to-lower direction as viewed laterally.

As illustrated in FIGS. 2, 3A, and 3C, a second reinforcement portion30B extending forward of the seat from a portion between upper and lowerends of the first reinforcement portion 30A is formed at the side frameside portion 12A forming the side portion of the side frame 12. As inthe first reinforcement portion 30A, the second reinforcement portion30B is configured as a bead portion formed in such a manner that part ofthe side frame side portion 12A is recessed inward of the seat bypressing. The second reinforcement portion 30B described herein isformed between the airbag attachment hole 31A and the airbag attachmenthole 31B. Note that a rear end of the second reinforcement portion 30Bis connected to the first reinforcement portion 30A, and the secondreinforcement portion 30B and the first reinforcement portion 30A areintegrated. Moreover, a front end of the second reinforcement portion30B is positioned forward of the seat with respect to the airbagattachment hole 31B, and is positioned backward of the seat with respectto a front edge of the side frame side portion 12A.

As illustrated in FIGS. 2, 3A, and 3C, a third reinforcement portion 30Cextending forward of the seat from the lower end of the firstreinforcement portion 30A is formed at the side frame side portion 12Aforming the side portion of the side frame 12. As in the firstreinforcement portion 30A, the third reinforcement portion 30C isconfigured as a bead portion formed in such a manner that part of theside frame side portion 12A is recessed inward of the seat by pressing.The third reinforcement portion 30C described herein is formed betweenthe airbag attachment hole 31A and the airbag attachment hole 31C. Notethat a rear end of the third reinforcement portion 30C is connected tothe first reinforcement portion 30A, and the third reinforcement portion30C and the first reinforcement portion 30A are integrated. Moreover, afront end of the third reinforcement portion 30C is positioned forwardof the seat with respect to the airbag attachment hole 31C, and ispositioned backward of the seat with respect to the front edge of theside frame side portion 12A.

FIG. 2 also illustrates a vertical line V at a position overlapping witha rear end of the third reinforcement portion 30C. As illustrated inFIG. 2, the rear end of the third reinforcement portion 30C is providedforward of the cross member 14. In other words, the cross member 14 isprovided at the rear of the third reinforcement portion 30C.

Moreover, as illustrated in FIG. 2, the second reinforcement portion 30Bextends from the first reinforcement portion 30A at an angle (i.e., asubstantially right angle) substantially perpendicular to a torso line Tindicating the axis of a body of a three-dimensional mannequin (notshown) representing the occupant seating on the vehicle seat includingthe seat frame 1 as the framework. On the other hand, the thirdreinforcement portion 30C extends from the first reinforcement portion30A at an angle (i.e., an acute angle) not perpendicular to the torsoline T. That is, the second reinforcement portion 30B and the thirdreinforcement portion 30C are different from each other in the angle ofextension from the first reinforcement portion 30A. As described above,the extension angles of the first reinforcement portion 30A, the secondreinforcement portion 30B, and the third reinforcement portion 30C varyso that stiffness against load input from various directions can beenhanced. Moreover, each of the first reinforcement portion 30A, thesecond reinforcement portion 30B, and the third reinforcement portion30C is, in the upper-to-lower direction, provided above the recliningunit 40.

Bottom portions (i.e., bottom portions of the beads) of the firstreinforcement portion 30A, the second reinforcement portion 30B, and thethird reinforcement portion 30C inside the seat are positioned outwardof the seat with respect to an end portion of a flange provided at thefront of the side frame 12. An upper end portion of the firstreinforcement portion 30A may be narrowed as compared to a lower endportion thereof. Front end portions of the second reinforcement portion30B and the third reinforcement portion 30C may be narrowed as comparedto rear portions thereof. The front end portions of the secondreinforcement portion 30B and the third reinforcement portion 30C may bepositioned forward of the front wall portion 13B of the lower frame 13,the support portion 15A of the pressure receiving member 15, attachmentportions of the reclining units 40, the headrest attachment portions 17,and the rotary shaft 16. Any of the first reinforcement portion 30A, thesecond reinforcement portion 30B, and the third reinforcement portion30C may be positioned forward of the headrest attachment portions 17.

As illustrated in FIG. 3B, a rear reinforcement portion 30D is formed ata center portion of the side frame rear portion 12B of the side frame12. A through-hole 31E and a through-hole 31F are each formed at upperand lower portions of the side frame rear portion 12B. The rearreinforcement portion 30D is configured as a bead portion formed in sucha manner that part of the side frame rear portion 12B is recessed inwardof the seat by pressing. The rear reinforcement portion 30D extends froma position facing the upper end of the first reinforcement portion 30Ato a position below the lower end of the first reinforcement portion30A. Moreover, the rear reinforcement portion 30D is formed such that anupper end of the rear reinforcement portion 30D is positioned above thethrough-hole 31E formed at the side frame rear portion 12B and a lowerend of the rear reinforcement portion 30D is positioned below thethrough-hole 31F formed at the side frame rear portion 12B. A centerportion of the rear reinforcement portion 30D positioned between thethrough-hole 31E and the through-hole 31F is a wide portion that iswider than the upper and lower ends. Moreover, the lower end of the rearreinforcement portion 30D is at a position overlapping with the lowerframe 13 in the upper-to-lower direction. As described above, the rearreinforcement portion 30D is formed at the side frame rear portion 12Bso that the strength of the side frame rear portion 12B can be enhancedacross a broad area.

As described above, an integrated inverted F-shaped bead portion of thefirst reinforcement portion 30A, the second reinforcement portion 30B,and the third reinforcement portion 30C is provided at the side frameside portion 12A of the side frame 12. Thus, the strength of the sideframe side portion 12A can be improved in a balanced manner across abroad area. Moreover, the first reinforcement portion 30A is providedalong the rear edge 12C so that the strength of the rear edge 12C can beenhanced. Further, the first reinforcement portion 30A is provided atleast at the wide portion 12D of the side frame side portion 12A, andtherefore, the strength of the wide portion 12D can be enhanced even inthe case of forming various through-holes for attaching components suchas the airbag to the wide portion 12D. In addition, the airbagattachment hole 31A is formed at a position sandwiched in theupper-to-lower direction by the second reinforcement portion 30B and thethird reinforcement portion 30C, and therefore, the strength of theperiphery of the airbag attachment hole 31A can be enhanced. Moreover,the second reinforcement portion 30B is provided between the airbagattachment hole 31A and the airbag attachment hole 31B, and therefore,the strength of the periphery of the airbag attachment hole 31A and theairbag attachment hole 31B can be enhanced. Further, the thirdreinforcement portion 30C is provided between the airbag attachment hole31A and the airbag attachment hole 31C, and therefore, the strength ofthe periphery of the airbag attachment hole 31A and the airbagattachment hole 31C can be enhanced.

Configurations of First Coupling Bracket 18 and Second Coupling Bracket19

Next, the configurations of the first coupling bracket 18 and the secondcoupling bracket 19 is described with reference to FIGS. 1 and 4 to 6C.

FIG. 4 is an enlarged partial view of the periphery of the secondcoupling bracket 19 from a view point IV of FIG. 1. FIGS. 5A, 5B, and 5Ceach correspond to an outer side view, a rear view, and an inner sideview of the first coupling bracket 18. FIGS. 6A, 6B, and 6C eachcorrespond to an outer side view, a rear view, and an inner side view ofthe second coupling bracket 19.

As illustrated in FIGS. 5A, 5B, and 5C, the first coupling bracket 18includes a weak portion 18A, a shaft through-hole 18B, a bolt fasteninghole 18C, and a bolt fastening hole 18D. The weak portion 18A is aportion provided between the shaft through-hole 18B and the boltfastening hole 18D and bent outward of the seat. In a case where a loadis input to the first coupling bracket 18, the first coupling bracket 18is easily deformable at the weak portion 18A. The rotary shaft 16 isinserted into the shaft through-hole 18B, and the left reclining unit 40is attached to the shaft through-hole 18B. The left side frame 12 iscoupled to the first coupling bracket 18 via the left reclining unit 40.The left cushion side frame 22A is fixed to the bolt fastening hole 18Cand the bolt fastening hole 18D with fastening tools such as bolts andnuts. For example, upon rear collision of the vehicle, the weak portion18A of the first coupling bracket 18 deforms to absorb impact.

As illustrated in FIGS. 6A, 6B, and 6C, the second coupling bracket 19includes a weak portion 19A, a shaft through-hole 19B, a bolt fasteninghole 19C, a bolt fastening hole 19D, and a weak portion 19E. The weakportion 19A is a portion provided between the shaft through-hole 19B andthe bolt fastening hole 19D and bent outward of the seat. In a casewhere a load is input to the second coupling bracket 19, the secondcoupling bracket 19 is easily deformable at the weak portion 19A. Therotary shaft 16 is inserted into the shaft through-hole 19B, and theright reclining unit 40 is attached to the shaft through-hole 19B. Theright side frame 12 is coupled to the second coupling bracket 19 via theright reclining unit 40. The right cushion side frame 22B is fixed tothe bolt fastening hole 19C and the bolt fastening hole 19D viafastening tools such as bolts and nuts. Moreover, the weak portion 19Eis a portion provided between the shaft through-hole 19B and the boltfastening hole 19C and bent outward of the seat. In a case where a loadis input to the second coupling bracket 19, the second coupling bracket19 is easily deformable at the weak portion 19E. For example, upon rearcollision of the vehicle, the weak portion 19A and the weak portion 19Eof the second coupling bracket 19 deform to absorb impact.

Note that regarding the weak portion 18A of the first coupling bracket18, a first connection portion with a shaft through-hole 18B side and asecond connection portion with a bolt fastening hole 18D side are at thesubstantially same position in the seat width direction. That is, at thefirst coupling bracket 18, the first connection portion and the secondconnection portion are not offset from each other in the seat widthdirection. On the other hand, regarding the weak portion 19A of thesecond coupling bracket 19, a second connection portion with a boltfastening hole 19D side is, in the seat width direction, positionedinward of the seat with respect to a first connection portion with ashaft through-hole 19B side. That is, at the second coupling bracket 19,the first connection portion and the second connection portion areoffset from each other in the seat width direction. Moreover, at thefirst coupling bracket 18, no weak portion is provided between the shaftthrough-hole 18B and the bolt fastening hole 18C. On the other hand, atthe second coupling bracket 19, the weak portion 19E is provided betweenthe shaft through-hole 19B and the bolt fastening hole 19C. As describedabove, the weak portion is provided unsymmetrically between the firstcoupling bracket 18 and the second coupling bracket 19, and therefore,ease of deformation upon load input to the seat frame 1 isdifferentiated.

As illustrated in FIG. 1, a height adjustment unit 41 is provided at theleft cushion side frame 22A, and a similar component is not provided atthe right cushion side frame 22B. Thus, a greater load is, upon rearcollision, input to the first coupling bracket 18 coupled to the leftcushion side frame 22A as compared to the second coupling bracket 19coupled to the right cushion side frame 22B. Meanwhile, at the seatframe 1, the weak portion is provided unsymmetrically between the firstcoupling bracket 18 and the second coupling bracket 19 as describedabove, and the second coupling bracket 19 is configured more easilydeformable than the first coupling bracket 18. Thus, deformation of thefirst coupling bracket 18 and the second coupling bracket 19 can beadjusted to the same level.

Configuration of Lower Frame 13

Next, a configuration of the lower frame 13 is described with referenceto FIGS. 7 to 11. FIG. 7 is a front view of the seat frame 1, and is anenlarged partial view of the periphery of the lower frame 13. FIG. 8 isa rear view of the seat frame 1, and is an enlarged partial view of theperiphery of the lower frame 13. FIG. 9 is an IX-IX sectional view ofFIG. 7, and FIG. 10 is an X-X sectional view of FIG. 7. FIG. 11 is aview from an arrow of a view point XI of FIG. 7, and is an enlargedpartial view of the lower frame 13.

As illustrated in FIGS. 7 to 11, the lower frame 13 includes a rear wallportion 13A forming a seat rear portion and having a J-shaped section,and the front wall portion 13B formed continuously to a front end of therear wall portion 13A and forming a seat front portion.

Configuration of Front Wall Portion 13B of Lower Frame 13

First, a configuration of the front wall portion 13B of the lower frame13 is mainly described. As illustrated in FIGS. 7 and 9, the front wallportion 13B is a portion formed in such a manner that a seat widthportion facing the support portion 15A is extended upward of the frontend of the rear wall portion 13A. As illustrated in FIG. 7, the wire 15Battached, at a lower end thereof, to three clips 50 is attached to thesupport portion 15A. Moreover, attachment portions 51 as through-holesin which the clips 50 are to be fitted are formed at three spots at thefront wall portion 13B. As illustrated in FIG. 7, the attachmentportions 51 are provided apart from the support portion 15A below thesupport portion 15A. Moreover, the attachment portions 51 are providedinward of ends of the support portion 15A in the right-to-leftdirection. The clips 50 attached to the wire 15B are fitted in theattachment portions 51 of the front wall portion 13B, and in thismanner, the wire 15B is fixed to the front wall portion 13B.

As illustrated in FIG. 7, an upper reinforcement portion 60A, an upperreinforcement portion 60B, and an upper reinforcement portion 60Cextending in the seat width direction are formed above the attachmentportion 51 of each clip 50 at the front wall portion 13B. As illustratedin FIG. 7, the upper reinforcement portion 60A, the upper reinforcementportion 60B, and the upper reinforcement portion 60C are formed on thesubstantially same horizontal plane. The upper reinforcement portion 60Ais provided on the left side, the upper reinforcement portion 60B isprovided at the center, and the upper reinforcement portion 60C isprovided on the right side. Note that the upper reinforcement portion60A, the upper reinforcement portion 60B, and the upper reinforcementportion 60C are formed as bead portions formed in such a manner thatpart of the front wall portion 13B is recessed backward of the seat bypressing.

As illustrated in FIG. 7, the upper reinforcement portion 60A, the upperreinforcement portion 60B, and the upper reinforcement portion 60C areformed in shapes along an upper edge of the front wall portion 13B. Thatis, the upper edge of the front wall portion 13B is in a linear shape atthe center and in an arc shape at right and left end portions.Accordingly, a left end portion of the upper reinforcement portion 60Ais formed in an arc shape, and other portions of the upper reinforcementportion 60A are formed in a linear shape. The upper reinforcementportion 60B is formed in a linear shape. A right end portion of theupper reinforcement portion 60C is formed in an arc shape, and otherportions of the upper reinforcement portion 60C are formed in a linearshape. The position of the left end portion of the upper reinforcementportion 60A is on the outside of the opposing attachment portion 51 inthe seat width direction. Similarly, the position of the right endportion of the upper reinforcement portion 60C is on the outside of theopposing attachment portion 51 in the seat width direction.

As illustrated in FIG. 7, a lower reinforcement portion 61A and a lowerreinforcement portion 61B apart from each other are formed below theattachment portion 51 facing the upper reinforcement portion 60A at aboundary portion between the front wall portion 13B and the rear wallportion 13A. The lower reinforcement portion 61A and the lowerreinforcement portion 61B are formed as bead portions formed in such amanner that the boundary portion between the front wall portion 13B andthe rear wall portion 13A is recessed backward of the seat by pressing.As illustrated in FIG. 7, the attachment portion 51 facing the upperreinforcement portion 60A is, in the seat upper-to-lower direction,provided between the upper reinforcement portion 60A and each of thelower reinforcement portion 61A and the lower reinforcement portion 61B.The position of the left end portion of the upper reinforcement portion60A is on the outside of the lower reinforcement portion 61A in the seatwidth direction. Moreover, the position of a right end portion of theupper reinforcement portion 60A is on the outside of the lowerreinforcement portion 61B in the seat width direction. That is, thelower reinforcement portion 61A and the lower reinforcement portion 61Bare, in the seat width direction, formed inward of the upperreinforcement portion 60A provided above the lower reinforcement portion61A and the lower reinforcement portion 61B. Moreover, a spacing betweenthe lower reinforcement portion 61A and the lower reinforcement portion61B is shorter than the length of the upper reinforcement portion 60A inthe width direction.

As illustrated in FIG. 7, a lower reinforcement portion 61C and a lowerreinforcement portion 61D apart from each other are formed below theattachment portion 51 facing the upper reinforcement portion 60B at theboundary portion between the front wall portion 13B and the rear wallportion 13A. The lower reinforcement portion 61C and the lowerreinforcement portion 61D are formed as bead portions formed in such amanner that the boundary portion between the front wall portion 13B andthe rear wall portion 13A is recessed backward of the seat by pressing.As illustrated in FIG. 7, the attachment portion 51 facing the upperreinforcement portion 60B is, in the seat upper-to-lower direction,provided between the upper reinforcement portion 60B and each of thelower reinforcement portion 61C and the lower reinforcement portion 61D.Moreover, the attachment portion 51 facing the upper reinforcementportion 60B is, in the seat width direction, provided between the lowerreinforcement portion 61C and the lower reinforcement portion 61D. Theposition of a left end portion of the upper reinforcement portion 60B ison the outside of the lower reinforcement portion 61C in the seat widthdirection. Moreover, the position of a right end portion of the upperreinforcement portion 60B is on the outside of the lower reinforcementportion 61D in the seat width direction. That is, the lowerreinforcement portion 61C and the lower reinforcement portion 61D are,in the seat width direction, formed inside the upper reinforcementportion 60B provided above the lower reinforcement portion 61C and thelower reinforcement portion 61D. Moreover, a spacing between the lowerreinforcement portion 61C and the lower reinforcement portion 61D isshorter than the length of the upper reinforcement portion 60B in thewidth direction.

As illustrated in FIG. 7, a lower reinforcement portion 61E and a lowerreinforcement portion 61F apart from each other are formed below theattachment portion 51 facing the upper reinforcement portion 60C at theboundary portion between the front wall portion 13B and the rear wallportion 13A. The lower reinforcement portion 61E and the lowerreinforcement portion 61F are formed as bead portions formed in such amanner that the boundary portion between the front wall portion 13B andthe rear wall portion 13A is recessed backward of the seat by pressing.As illustrated in FIG. 7, the attachment portion 51 facing the upperreinforcement portion 60C is, in the seat upper-to-lower direction,provided between the upper reinforcement portion 60C and each of thelower reinforcement portion 61E and the lower reinforcement portion 61F.The position of a left end portion of the upper reinforcement portion60C is on the outside of the lower reinforcement portion 61E in the seatwidth direction. Moreover, the position of the right end portion of theupper reinforcement portion 60C is on the outside of the lowerreinforcement portion 61F in the seat width direction. That is, thelower reinforcement portion 61E and the lower reinforcement portion 61Fare, in the seat width direction, formed inside the upper reinforcementportion 60C provided above the lower reinforcement portion 61E and thelower reinforcement portion 61F. Moreover, a spacing between the lowerreinforcement portion 61E and the lower reinforcement portion 61F isshorter than the length of the upper reinforcement portion 60C in thewidth direction.

As illustrated in FIG. 7, a spacing between the upper reinforcementportion 60A and the upper reinforcement portion 60B adjacent to eachother on the upper side is shorter than a spacing between the lowerreinforcement portion 61B and the lower reinforcement portion 61Cadjacent to each other on the lower side. Similarly, a spacing betweenthe upper reinforcement portion 60B and the upper reinforcement portion60C adjacent to each other on the upper side is shorter than a spacingbetween the lower reinforcement portion 61D and the lower reinforcementportion 61E adjacent to each other on the lower side.

For example, in the case of attaching the pressure receiving member 15to a front surface of the rear wall portion 13A, the process ofattaching the pressure receiving member 15 is not easy because therotary shaft 16 is provided between the rear wall portion 13A and thefront wall portion 13B and there is not sufficient space. Meanwhile, atthe seat frame 1, the attachment portions 51 for attaching the wire 15Bof the pressure receiving member 15 are provided at the front wallportion 13B of the lower frame 13, and therefore, the rotary shaft 16and an engineer's hand (not shown) do not contact each other. Thus,workability in attachment of the pressure receiving member 15 can beimproved.

Configuration of Rear Wall Portion 13A of Lower Frame 13

Next, a configuration of the rear wall portion 13A of the lower frame 13is mainly described. As illustrated in FIG. 9, an upper end of the rearwall portion 13A is positioned above an upper end of the front wallportion 13B. Moreover, a lower end of the support portion 15A ispositioned above the upper end of the front wall portion 13B and belowthe upper end of the rear wall portion 13A. Moreover, as illustrated inFIG. 9, the front wall portion 13B is provided substantially parallel tothe support portion 15A. Note that the support portion 15A issubstantially parallel to the torso line T, and in other words, thefront wall portion 13B is provided substantially parallel to the torsoline T.

As illustrated in FIG. 8, upwardly-protruding portions 75 protrudingupward are each provided at both upper outer portions of the rear wallportion 13A in the seat width direction. The upwardly-protruding portion75 is formed in a shape along the side frame 12, and a reinforcementportion 74 is formed at a position facing the rear reinforcement portion30D of the side frame 12. Note that the reinforcement portion 74 isformed as a bead portion recessed forward of the seat, and is in a shapeengageable with the rear reinforcement portion 30D. Note that both sideportions of the rear wall portion 13A in the seat width direction arejoined to the side frames 12 by welding.

According to the seat frame 1 of the present embodiment as describedabove, the first reinforcement portion 30A, the second reinforcementportion 30B, and the third reinforcement portion 30C are provided at theside frame side portion 12A of the side frame 12, and therefore, thestiffness of the side frame 12 can be improved. The first reinforcementportion 30A, the second reinforcement portion 30B, and the thirdreinforcement portion 30C described herein are different from each otherin an extension direction, and therefore, the stiffness against loadinput from various directions can be improved.

Moreover, according to the seat frame 1, the attachment portions 51 ofthe pressure receiving member 15 are provided at the front wall portion13B of the lower frame 13, and therefore, the workability in attachmentof the pressure receiving member 15 can be improved. Moreover, thereinforcement portions are provided on the upper and lower sides of theattachment portions 51 at the front wall portion 13B, and therefore, thestiffness of the periphery of the attachment portions 51 can beimproved.

Variations

The present disclosure is not limited to the above-described embodiment.Hereinafter, variations of the reinforcement portions (bead shapes)formed at the side frame side portion 12A of the side frame 12 aredescribed with reference to FIGS. 12A to 12D. FIGS. 12A to 12D eachillustrate outer side views of the side frames 12 according to thevariations.

First, the side frame 12 according to a first variation is described. Asillustrated in FIG. 12A, the side frame 12 according to the firstvariation includes a reinforcement portion 80A, a reinforcement portion80B, a reinforcement portion 80C, a reinforcement portion 80D, and areinforcement portion 80E. Each of the reinforcement portion 80A, thereinforcement portion 80B, the reinforcement portion 80C, thereinforcement portion 80D, and the reinforcement portion 80E describedherein is formed as a bead portion formed in such a manner that the sideframe side portion 12A is recessed inward of the seat by pressing. Thereinforcement portion 80A is provided along the rear edge 12C of theside frame side portion 12A. The reinforcement portion 80B is providedto extend in the seat front-to-rear direction between the airbagattachment hole 31A and the airbag attachment hole 31B. Thereinforcement portion 80C is provided to extend in the seatfront-to-rear direction between the airbag attachment hole 31A and theairbag attachment hole 31C. The reinforcement portion 80D is provided toextend in the seat front-to-rear direction below the airbag attachmenthole 31C. The reinforcement portion 80E is provided along the front edgeof the side frame side portion 12A above the airbag attachment hole 31B.

As illustrated in FIG. 12A, any of the reinforcement portion 80A, thereinforcement portion 80B, the reinforcement portion 80C, thereinforcement portion 80D, and the reinforcement portion 80E is notnecessarily coupled to other reinforcement portions, and may be providedas independent bead portions. Moreover, the reinforcement portion 80A,the reinforcement portion 80B, the reinforcement portion 80C, thereinforcement portion 80D, and the reinforcement portion 80E may bedifferent from each other in their respective extension directions.

Next, the side frame 12 according to a second variation is described. Asillustrated in FIG. 12B, the side frame 12 according to the secondvariation includes a reinforcement portion 81A, a reinforcement portion81B, and a reinforcement portion 81C. Each of the reinforcement portion81A, the reinforcement portion 81B, and the reinforcement portion 81Cdescribed herein is formed as a bead portion formed in such a mannerthat the side frame side portion 12A is recessed inward of the seat bypressing. The reinforcement portion 81A is provided along the rear edge12C of the side frame side portion 12A. Note that a lower end of thereinforcement portion 81A is curved inward of the seat. Thereinforcement portion 81B is provided to extend in the seatfront-to-rear direction between the airbag attachment hole 31A and theairbag attachment hole 31B. Moreover, a rear end of the reinforcementportion 81B is coupled to the reinforcement portion 81A. Thereinforcement portion 81C is provided along the front edge of the sideframe side portion 12A above the airbag attachment hole 31B.

Next, the side frame 12 according to a third variation is described. Asillustrated in FIG. 12C, the side frame 12 according to the thirdvariation includes a reinforcement portion 82A, a reinforcement portion82B, a reinforcement portion 82C, and a reinforcement portion 82D. Eachof the reinforcement portion 82A, the reinforcement portion 82B, thereinforcement portion 82C, and the reinforcement portion 82D describedherein is formed as a bead portion formed in such a manner that the sideframe side portion 12A is recessed inward of the seat by pressing. Thereinforcement portion 82A is provided along the rear edge 12C of theside frame side portion 12A. Note that a lower end of the reinforcementportion 82A is bent inward of the seat. The reinforcement portion 82B isprovided to extend in the seat front-to-rear direction between theairbag attachment hole 31A and the airbag attachment hole 31B. Moreover,a rear end of the reinforcement portion 82B is coupled to thereinforcement portion 82A. The reinforcement portion 82C is provided toextend in the seat front-to-rear direction from a bent portion of thereinforcement portion 82A to the airbag attachment hole 31C. Moreover, arear end of the reinforcement portion 82C is coupled to thereinforcement portion 82A. The reinforcement portion 82D is providedalong the front edge of the side frame side portion 12A above the airbagattachment hole 31B.

Next, the side frame 12 according to a fourth variation is described. Asillustrated in FIG. 12D, the side frame 12 according to the fourthvariation includes a reinforcement portion 83A, a reinforcement portion83B, and a reinforcement portion 83C. Each of the reinforcement portion83A, the reinforcement portion 83B, and the reinforcement portion 83Cdescribed herein is formed as a bead portion formed in such a mannerthat the side frame side portion 12A is recessed inward of the seat bypressing. The reinforcement portion 83A is provided along the rear edge12C of the side frame side portion 12A. The reinforcement portion 83B isformed in an annular ring shape, and at a rear end portion thereof, iscoupled to the reinforcement portion 83A. Moreover, the reinforcementportion 83B is formed among the airbag attachment hole 31A, the airbagattachment hole 31B, and the airbag attachment hole 31C, and includesthe airbag attachment hole 31A. The reinforcement portion 83C isprovided along the front edge of the side frame side portion 12A abovethe airbag attachment hole 31B.

Second Embodiment

Next, a seat frame 1 according to a second embodiment is described withreference to FIGS. 13 to 18. In the seat frame 1 according to the secondembodiment, a cross member 100 bridged at an upper frame 11 is differentfrom the cross member 14 illustrated in FIG. 1 as described below, butother points are common to the first and second embodiments. Thus, aconfiguration of the cross member 100 is described below.

As illustrated in FIG. 13, the cross member 100 extending in the seatwidth direction is bridged between right and left bent portions of theupper frame 11. Right and left end portions 103 of the cross member 100are welded and fixed to the right and left bent portions of the upperframe 11.

At an upper end of the cross member 100, a first recessed portion 101recessed downward is formed between the right and left end portions 103.Note that in the case of providing the first recessed portion 101 at alower end of the cross member 100, the first recessed portion 101 is ina shape recessed upward between the right and left end portions 103.

As illustrated in FIGS. 13 and 14, the first recessed portion 101 isprovided at a center portion of the cross member 100 in the seat widthdirection. Note that the center portion of the cross member 100 in theseat width direction is between right and left headrest attachmentportions 17.

The cross member 100 has wide portions 105 on the right and left sidesof the first recessed portion 101 in the seat width direction. The wideportion 105 is configured such that the width thereof in theupper-to-lower direction is greater than that of the first recessedportion 101. Note that the cross member 100 is in a symmetrical shapewith respect to the first recessed portion 101 in the right-to-leftdirection. That is, the shapes of the right and left wide portions 105are symmetrical in the right-to-left direction.

As illustrated in FIG. 14, the wide portion 105 is curved to protrudebackward of the seat. Specifically, an outer portion of the wide portion105 in the seat width direction is curved in a shape protruding backwardof the seat.

As illustrated in FIGS. 13 to 17, a reinforcement portion 104 is formedat a center portion of the cross member 100 in the upper-to-lowerdirection. The reinforcement portion 104 is formed across the firstrecessed portion 101 and the right and left wide portions 105. Thereinforcement portion 104 protrudes forward of the seat. Specifically,the reinforcement portion 104 is configured as a bead portion formed insuch a manner that part of the cross member 100 is projected forward ofthe seat by pressing, for example. Thus, the stiffness of the crossmember 100 is improved. Note that as illustrated in FIG. 13, thereinforcement portion 104 of the wide portion 105 is wider in theupper-to-lower direction than the reinforcement portion 104 of the firstrecessed portion 101.

As illustrated in FIG. 13, a first through-hole 106 and a secondthrough-hole 107 are formed at the reinforcement portion 104 at the wideportion 105. The first through-hole 106 is a rectangular through-hole,and the second through-hole 107 is a circular through-hole. As describedabove, the shapes of the through-holes formed at the reinforcementportion 104 of the wide portion 105 are not specifically limited. Notethat the through-holes such as the first through-hole 106 and the secondthrough-hole 107 are formed at the cross member 100, and therefore, theweight of the cross member 100 can be reduced.

As illustrated in FIGS. 13 to 17, a first flange portion 108A is formedat an upper end portion of the cross member 100. The first flangeportion 108A is a portion formed in such a manner that the upper endportion of the cross member 100 is bent forward of the seat. Moreover,the first flange portion 108A is formed across the first recessedportion 101 and the right and left wide portions 105. The first flangeportion 108A is formed at a position facing the first recessed portion101 in the upper-to-lower direction. That is, the first flange portion108A is formed above the first recessed portion 101.

A second recessed portion 102A recessed downward of the seat is formedat the first flange portion 108A of the wide portion 105. In otherwords, the second recessed portion 102A is a recessed portion providedat the upper end of the cross member 100 and formed differently from thefirst recessed portion 101. A portion below the second recessed portion102A protrudes forward of the seat.

As illustrated in FIGS. 13 to 17, a second flange portion 108B is formedat a lower end portion of the cross member 100. The second flangeportion 108B is a portion formed in such a manner that the lower endportion of the cross member 100 is bent forward of the seat. Moreover,the second flange portion 108B is formed across the first recessedportion 101 and the right and left wide portions 105.

A second recessed portion 102B recessed upward of the seat is formed atthe second flange portion 108B of the wide portion 105. In other words,the second recessed portion 102B is a recessed portion provided at thelower end of the cross member 100 and formed differently from the firstrecessed portion 101. A portion above the second recessed portion 102Bprotrudes forward of the seat.

The second recessed portion 102A, the first through-hole 106, and thesecond recessed portion 102B are arranged at positions overlapping witheach other in the upper-to-lower direction.

Note that the above-described cross member 100 has both of the firstflange portion 108A and the second flange portion 108B, but may haveeither one of the first flange portion 108A or the second flange portion108B.

An example of attachment of a member to the cross member 100 of the seatframe 1 according to the second embodiment is described with referenceto FIG. 18. As illustrated in FIG. 18, a blower 92 is attached to abovethe first recessed portion 101 of the cross member 100. Specifically, anattachment member 90 is fixed between the upper frame 11 and the firstrecessed portion 101 of the cross member 100. For example, theattachment member 90 is a metal plate-shaped plate. The attachmentmember 90 is welded to the upper frame 11 and the first recessed portion101 of the cross member 100 at welding portions 91.

Using fasteners 93 such as screws, the blower 92 is fixed to theattachment member 90. Thus, the blower 92 can be arranged in a spaceabove the first recessed portion 101 of the cross member 100. Asdescribed above, the first recessed portion 101 is in a shape recesseddownward, and therefore, a greater space than the wide portion 105 isformed above the first recessed portion 101 of the cross member 100.Thus, a relatively-large member such as the blower 92 can be arrangedabove the first recessed portion 101.

Stop portions 95 of cover portions 94 can be attached to the secondrecessed portion 102A and the second recessed portion 102B of the crossmember 100. For example, in a case where the stop portion 95 is a hook,the hook is stopped at a protruding portion of the second recessedportion 102A (or the second recessed portion 102B), and in this manner,the stop portion 95 can be attached to the second recessed portion 102A(or the second recessed portion 102B). As described above, variousmembers can be attached to the cross member 100.

Advantageous Effects of Seat Frame 1

The seat frame 1 includes the side frames 12 arranged on the right andleft sides, and has the first reinforcement portion 30A extending in theupper-to-lower direction along the rear edge of the side frame sideportion 12A positioned outside in the seat width direction at the sideframe 12. According to the seat frame 1, the rear edge of the side frameside portion 12A is reinforced so that the stiffness of the side frame12 can be improved.

Moreover, in the seat frame 1, the first reinforcement portion 30A isprovided at least at the wide portion having the greatest width in theseat front-to-rear direction at the side frame side portion 12A. Withthis configuration, the wide portion of the side frame side portion 12Ais reinforced so that the stiffness of the side frame 12 can beimproved.

Further, the seat frame 1 has the second reinforcement portion 30Bprovided at the side frame side portion 12A and extending in the seatfront-to-rear direction, and the second reinforcement portion 30B isprovided within an upper-to-lower area where the first reinforcementportion 30A extends. With this configuration, the side frame sideportion 12A is reinforced in the upper-to-lower direction and thefront-to-rear direction, and therefore, the stiffness of the side frame12 can be improved.

In addition, in the seat frame 1, the first reinforcement portion 30Aand the second reinforcement portion 30B are coupled to each other. Withthis configuration, the first reinforcement portion 30A and the secondreinforcement portion 30B can be integrally formed. Thus, formation ofthe reinforcement portions is facilitated.

Moreover, the seat frame 1 has the third reinforcement portion 30Cprovided at the side frame side portion 12A and extending in thefront-to-rear direction at a position apart in a downward direction fromthe second reinforcement portion 30B. With this configuration, thestiffness of the side frame side portion 12A can be improved across abroad area.

Further, in the seat frame 1, the second reinforcement portion 30B iscoupled to the portion between the upper and lower ends of the firstreinforcement portion 30A, and the third reinforcement portion 30C iscoupled to the lower end of the first reinforcement portion 30A. Withthis configuration, the stiffness of the side frame side portion 12A canbe improved in a balanced manner.

In addition, in the seat frame 1, the second reinforcement portion 30Band the third reinforcement portion 30C are different from each other inthe angle of extension with respect to the first reinforcement portion30A. With this configuration, the stiffness against load input fromvarious directions can be improved.

Moreover, in the seat frame 1, the second reinforcement portion 30Bextends in the direction substantially perpendicular to the torso lineT. With this configuration, stiffness on a high load input side can beimproved.

Further, in the seat frame 1, the second reinforcement portion 30Bextends between the multiple through-holes formed at the side frame sideportion 12A. With this configuration, the stiffness of the periphery ofthe through-holes can be improved.

In addition, in the seat frame 1, the multiple through-holes include theairbag attachment hole 31A for attaching the airbag, and the secondreinforcement portion 30B and the third reinforcement portion 30C areprovided at the positions sandwiching the airbag attachment hole 31A inthe upper-to-lower direction. With this configuration, the stiffness ofa portion of the side frame 12 attached to the airbag can be improved.

Moreover, in the seat frame 1, the first reinforcement portion 30A is atthe position facing at least one of the multiple through-holes in theupper-to-lower direction. With this configuration, the stiffness of theperiphery of the through-holes of the side frame 12 can be improved.

Further, the seat frame 1 includes the upper frame 11 coupling the upperportions of the side frames 12, and the side frame side portion 12A isjoined to the upper frame side portion 11A positioned outside in theseat width direction at the upper frame 11. Moreover, the firstreinforcement portion 30A is provided at the position at which the sideframe side portion 12A and the upper frame side portion 11A overlap witheach other. With this configuration, the stiffness of the joint portionbetween the side frame 12 and the upper frame 11 can be improved.

In addition, the seat frame 1 includes the upper frame 11 forming anupper portion of the seat back frame 10, and the cross member 100bridged at the upper frame 11. The cross member 100 has the right andleft end portions 103, which are fixed to the upper frame 11, in theseat width direction, and the first recessed portion 101 recessed upwardor downward between the right and left end portions 103. According tothe seat frame 1, the weight of the cross member 100 can be reduced ascompared to the case of providing no recessed portion at the crossmember 100. With this configuration, the weight of the cross member 100bridged between the right and left sides of the seat frame 1 can bereduced.

Moreover, in the seat frame 1, the first recessed portion 101 isprovided at the center portion of the cross member 100 in the seat widthdirection. As described above, the first recessed portion is provided ata position facing the occupant, and therefore, a feeling of sitting onthe seat can be improved. Further, according to the seat frame 1, thespace where a member such as the blower 92 is arranged can be providedin the vicinity of the center portion of the cross member 100.

In addition, in the seat frame 1, the cross member 100 has thereinforcement portion 104 formed at the first recessed portion 101. Withthis configuration, lowering of the stiffness of the vicinity of thefirst recessed portion 101 of the cross member 100 can be suppressed.

Moreover, in the seat frame 1, the cross member 100 has the wideportions 105 provided on the right and left sides of the first recessedportion 101 in the seat width direction, and the reinforcement portion104 is formed across the first recessed portion 101 and both of the wideportions 105. With this configuration, the stiffness of the cross member100 can be improved.

Further, in the seat frame 1, the cross member 100 is provided with thethrough-holes (the first through-hole 106, the second through-hole 107).With this configuration, the weight of the cross member 100 can befurther reduced.

In addition, in the seat frame 1, the through-holes (the firstthrough-hole 106, the second through-hole 107) are formed at the wideportion 105. The through-holes (the first through-hole 106, the secondthrough-hole 107) are formed at the wide portion 105 as described above,and therefore, larger through-holes can be formed as compared to thecase of forming the through-holes at the first recessed portion 101.With this configuration, the weight of the cross member 100 can befurther reduced.

Moreover, in the seat frame 1, the through-holes (the first through-hole106, the second through-hole 107) are formed at the reinforcementportion 104 of the wide portion 105. With this configuration, the weightof the cross member 100 can be reduced, and lowering of the stiffness ofthe cross member 100 can be also suppressed.

Further, in the seat frame 1, at least part of the wide portion 105 iscurved to protrude backward. With this configuration, the stiffness ofthe cross member 100 can be improved. Moreover, the cross member 100 canbe formed in a shape matching the body shape of the occupant, andtherefore, the feeling of sitting on the seat can be improved.

In addition, the seat frame 1 has the second recessed portion (thesecond recessed portion 102A, the second recessed portion 102B)different from the first recessed portion 101, the second recessedportion being provided at least at one of the upper or lower end of thecross member 100. With this configuration, the weight of the crossmember 100 can be further reduced. Moreover, a member such as the stopportion 95 of the cover portion 94 can be stopped at the second recessedportion (the second recessed portion 102A, the second recessed portion102B). Thus, the number of components forming the seat can be reduced.Consequently, the weight of the seat can be reduced.

Further, the seat frame 1 has the flange portion (the first flangeportion 108A, the second flange portion 108B) provided at least at oneof the upper or lower end of the cross member 100. The flange portion(the first flange portion 108A, the second flange portion 108B) isformed at the position facing the first recessed portion 101 in theupper-to-lower direction. With this configuration, the stiffness of thefirst recessed portion 101 can be improved.

TABLE OF REFERENCE NUMERALS

-   1: seat frame-   10: seat back frame-   11: upper frame    -   11A: upper frame side portion-   12: side frame    -   12A: side frame side portion    -   12B: side frame rear portion    -   12C: rear edge    -   12D: wide portion-   13: lower frame    -   13A: rear wall portion    -   13B: front wall portion-   14: cross member    -   14A: recessed portion    -   14B: end portion-   15: pressure receiving member    -   15A: support portion    -   15B: wire    -   15C: wire-   16: rotary shaft-   17: headrest attachment portion-   18: first coupling bracket    -   18A: weak portion    -   18B: shaft through-hole    -   18C: bolt fastening hole    -   18D: bolt fastening hole-   19: second coupling bracket    -   19A: weak portion    -   19B: shaft through-hole    -   19C: bolt fastening hole    -   19D: bolt fastening hole    -   19E: weak portion-   20: seat cushion frame-   21: pan frame-   22A, 22B: cushion side frame-   23: coupling pipe-   24: pressure receiving member-   30A: first reinforcement portion-   30B: second reinforcement portion-   30C: third reinforcement portion-   30D: rear reinforcement portion-   31A: airbag attachment hole-   31B: airbag attachment hole-   31C: airbag attachment hole-   31D: through-hole-   31E: through-hole-   31F: through-hole-   40: reclining unit-   41: height adjustment unit-   50: clip-   51: attachment portion-   52: welding portion-   60A: upper reinforcement portion-   60B: upper reinforcement portion-   60C: upper reinforcement portion-   61A: lower reinforcement portion-   61B: lower reinforcement portion-   61C: lower reinforcement portion-   61D: lower reinforcement portion-   61E: lower reinforcement portion-   61F: lower reinforcement portion-   74: reinforcement portion-   75: upwardly-protruding portion-   80A: reinforcement portion-   80B: reinforcement portion-   80C: reinforcement portion-   80D: reinforcement portion-   80E: reinforcement portion-   81A: reinforcement portion-   81B: reinforcement portion-   81C: reinforcement portion-   82A: reinforcement portion-   82B: reinforcement portion-   82C: reinforcement portion-   82D: reinforcement portion-   83A: reinforcement portion-   83B: reinforcement portion-   83C: reinforcement portion-   90: attachment member-   91: welding portion-   92: blower-   93: fastener-   94: cover portion-   95: stop portion-   100: cross member-   101: first recessed portion-   102A: second recessed portion-   102B: second recessed portion-   103: end portion-   104: reinforcement portion-   105: wide portion-   106: first through-hole-   107: second through-hole-   108A: first flange portion (flange portion)-   108B: second flange portion (flange portion)-   T: torso line-   V: vertical line

1. A seat frame of a vehicle seat, comprising: an upper frame forming anupper portion of a seat back frame; and a cross member bridged at theupper frame, wherein the cross member includes right and left endportions in a seat width direction, the right and left end portionsbeing fixed to the upper frame, and a first recessed portion that isrecessed upward or downward and provided between the right and left endportions.
 2. The seat frame according to claim 1, wherein the firstrecessed portion is provided at a center portion of the cross member inthe seat width direction.
 3. The seat frame according to claim 1,wherein the cross member includes a reinforcement portion formed at thefirst recessed portion.
 4. The seat frame according to claim 3, whereinthe cross member includes wide portions provided on right and left sidesof the first recessed portion in the seat width direction, and thereinforcement portion is formed across the first recessed portion andboth of the wide portions.
 5. The seat frame according to claim 4,wherein the cross member is provided with a through-hole.
 6. The seatframe according to claim 5, wherein the through-hole is formed at eachwide portion.
 7. The seat frame according to claim 6, wherein thethrough-hole is formed at the reinforcement portion at each wideportion.
 8. The seat frame according to claim 4, wherein at least partof each wide portion is curved to protrude backward.
 9. The seat frameaccording to claim 1, further comprising: a second recessed portiondifferent from the first recessed portion, the second recessed portionbeing provided at least at one of an upper or lower end of the crossmember.
 10. The seat frame according to claim 1, further comprising: aflange portion provided at least at one of an upper or lower end of thecross member, wherein the flange portion is formed at a position facingthe first recessed portion in an upper-to-lower direction.